1. Field of the Invention
The invention relates to an endoscopic surgical instrument. More particularly, the invention relates to a flexible instrument for the transoral invagination and fundoplication of the stomach to the esophagus.
2. State of the Art
Gastroesophageal fundoplication is a procedure for the treatment of gastroesophageal reflux disease (GERD), a condition in which gastric acids are regurgitated into the esophagus resulting in esophagitis, intractable vomiting, asthma, and aspiration pneumonia. The fundoplication procedure involves wrapping the fundus of the stomach around the lower end of the esophagus and fastening it in place. Traditionally, this procedure is accomplished via open surgery with the use of sutures to secure the plicated fundus of the stomach around the esophagus without penetrating (incising) the stomach.
U.S. Pat. No. 5,403,326 to Harrison et al. discloses a method of performing endoscopic fundoplication using surgical staples or two-part surgical fasteners. The procedure disclosed by Harrison et al. involves performing two percutaneous endoscopic gastrotomies (incisions through the skin into the stomach) and the installation of two ports through which a stapler, an endoscope, and an esophageal manipulator (invagination device) are inserted. Under view of the endoscope, the esophageal manipulator is used to pull the interior of the esophagus into the stomach. When the esophagus is in position, with the fundus of the stomach plicated, the stapler is moved into position around the lower end of the esophagus and the plicated fundus is stapled to the esophagus. The process is repeated at different axial and rotary positions until the desired fundoplication is achieved. While, the procedure disclosed by Harrison et al. is a vast improvement over open surgery, it is still relatively invasive requiring two incisions through the stomach. Moreover, the procedure requires the manipulation of two different tools in order to position the fundus and to secure the fundus to the esophagus.
U.S. Pat. No. 5,571,116 to Bolanos et al. discloses a non-invasive treatment of gastroesophageal reflux disease which utilizes a remotely operable invagination device and a remotely operable surgical stapler, both of which are inserted transorally through the esophagus. According to the methods disclosed by Bolanos et al., the invagination device is inserted first and is used to clamp the gastroesophageal junction. The device is then moved distally, pulling the clamped gastroesophageal junction into the stomach, thereby invaginating the junction and involuting the surrounding fundic wall. The stapler is then inserted transorally and delivered to the invaginated junction where it is used to staple the fundic wall.
Bolanos et al. disclose several different invagination devices and several different staplers. Generally, each of the staplers disclosed by Bolanos et al. has an elongate body and a spring biased anvil which is rotatable approximately 15.degree. away from the body in order to locate the invaginated gastroesophageal junction between the body and the anvil. The body contains a staple cartridge holding a plurality of staples, and a staple firing knife. Each of the invagination devices disclosed by Bolanos et al. has a jaw member which is rotatable at least 45.degree. and in some cases more than 90.degree. to an open position for grasping the gastroesophageal junction. One of the chief disadvantages of the methods and apparatus disclosed by Bolanos et al. is that the stapler and the invagination device must be both be present in the esophagus at the same time. With some of the embodiments disclosed, the presence of both instruments is significantly challenged by the size of the esophagus. In all of the embodiments, the invagination device is always laterally spaced apart from the stapler. Thus, the stapler cannot staple the invaginated tissue, per se, but can only staple tissue which is laterally adjacent to the invaginated tissue. The relatively small rotational movement of the anvil of the stapler further complicates the accommodation of tissue adjacent to the invaginated tissue. In addition, surgical staples have some inherent disadvantages as compared to other fasteners. The relatively small surface area of surgical staples allows them to pass through tissue over time, thereby unfastening the tissue and allowing the staples to migrate to other parts of the body. Bolanos et al. appears to recognize this disadvantage and proposes the application of a bolster or pledger to the tissues prior to stapling. Bolanos et al. do not explain how this can be accomplished transorally using the apparatus disclosed. In addition, while Bolanos et al. make a broad reference to other types of fasteners, the substantial size constraints imposed on the apparatus which are delivered transorally would seem to prohibit any type of fastener other than the staples shown by Bolanos et al. The actuating mechanism of the device disclosed by Bolanos et al. is somewhat awkward. In particular, the stapler anvil is biased to the open position, and it is not clear whether or not the stapler anvil can be locked in a closed position without continuously holding down a lever. In addition, it appears that the staple firing trigger can be inadvertently operated before the anvil is in the closed position. This would result in inadvertent ejection of staples into the stomach or the esophagus of the patient.